Internal-combustion engine valve



Jam. M, WW P. A. JENNINGS V INTERNAL-COMBUSTION ENGINE VALVE Filed Aug. 25, 1948 20035 hzwommm Om Om OW OM (NH mac: 'os ISWS) ,LHSIEHM W S801 INVENTOR. PAUL A. JENINGS HIS A! i RNEY I my copending application Serial No. 19,293, filed i'uel intake side oi the engine, and reach anyponents which are especially useful at high engines, especially in the vicinity of the exhaust Patented Jan. 31, 1950 Q i UNITED s'rArss PATENT OFFICE INTERNAL-COMBUSTION ENGINE VALVE Paul A. Jennings, Baltimore, Md, minor to Armco Steel Corporation, a corporation of Ohio Application August 25, 1848, Serial No. 46,085

.7 Claims. rout-12s) 2 This application is a continuation-impart offrequently so as high as 700 F. or more on the Arpil 6, i948, and the invention relates to high where from about r100 F. to 1450 F. or more on temperature stainless steel and more particu-= the exhaust side. These temperatures usually larly to stainless steel valves and valve coma are even more severe in bus, truck and aeroplane temperatures and in corrosive atmospheres. valves.

An object of my invention is the provision of Low-alloy steel valves usually warp or burn strong, tough and durable austenitic stainless very quickly at modern-day engine temperatures, steel valves and other internal combustion engine to thus impairing efllciency and requiring frequent components, which in view of the excellent propreplacement. In the exhaust valve position, the cities of the particular steel employed, function steel products sufier all the more and soon fail to in a highly satisfactory manner in such fields as seat properly, this then allowing the hot-engine passenger car, truck, bus. aircraft, Diesel and cases to blow by. addins to the destruction of the marine vessel engine use. in metal and its functions.

it further object of my invention is the pro Quite some few stainless steel valves, and valves vision oi stainless steel products and articles of do of other high-alloy metal have been introthe character indicated which have substantial duced on the marlret to better serve present day resistance to creep in the heated condition, and n ds. Amon these r hls whr m m, hithtvnich are highly hot-hard at the elevated .temno silicon products. These essentially are ierritic,

peraturcs encountered. and possess many desirable properties including ii. still further object of my invention is the high resistance to scaling b heat. They. are provision of products and articles of the charusually not so strono, however, at high temacter indicated which in the heated condition heratures. are highly resistant to hot corrosive atmospheres 2. Apart from the i'erritic stainless steel valves, such as those containing the combustion products there are valves in the prior art made of certain pi anti-knock leaded fuels illustratively of the grades of austenitic stainless .steel. The :aus tpigraethyl d gasoline variety, tenitic steels have the characteristic of being sub- Other objects oi my invention in part will be stantially tree oi phase transformation and thus, obvious and in part pointed out more fully hereindo n this respect. are free of volume changes, warpmi ing, sticking or cracking during heating and The invention accordingly consists in the comcooling 31 6 uch about by e m tor. It hination of elements, composition of materials m y also be Said that valves made of theausand features or products, and in the relation 02 1581111110 Stainless l s a general class have a h of th same t one or more 1; th others as 35 more favorable lattice structure for resisting described herein, the scope or the application of stressfirupture a l va ed te peratures than do which is indicated in the following claims. ierritic or martensitic products. Despite this,

In the accompanying drawing, the single figure however, many of the heretofore known austererepresents the effect of silicon content or coritic stainless steel valves leave much to be desired melon-resistance in molten lead oxide of chro- M of resistance to heat and corrosive attack, espen lium-niclrel-molybdenum stainless steel. cially where the metal is subjected to the com- As conducive to a clearer understanding of bustion products of leaded fuels. Certain of the certain features of my invention, it may be noted heretofore known austenitic products also lack at this point that a great number of low-alloy resistance o deformation. or ail o adi y by steel valves, which formerly operated to some an c ep a S sup r While h at d and n degree of satisfaction at comparatively low temi fln- It is further ue ha Cert n of the peratures, are now found in many insta t austenitic stainless steel internal combustion be unacceptable. With increased engine speeds engine val e or ike products too readily suffer and greater power demands in recent years, as stretch as where, for example, in the form oi oi aeroplanes, trucks, pleasure cars, and the like, my poppet valves. In this connection, any substanand the concurrent use of fuels of the so-called tial stretch of the metal at the operating temanti-knocl: leaded varieties, the engine valves perature of the valve material usually is fatal to meet a severe combination of heat, corrosive and proper seating. mechanical efl'ects. In ordinary pleasure cars, .Anoutstanding object of my invention, accordthe temperatures to which the valves are exposed, on ingly, is the provision of strong, hot-hard and 3 I durable austenitic stainless steel high temperature valves, valve parts, and any of a variety of other high temperature heat and corrosionresistant components, as .for internal combustion engines, which components are resistant to creep and stress-rupture, reliably resist heat scaling, and which are capable of withstanding attack by combustion products of leaded fuels.

Referring now more particularly to the practice of my invention, I provide high temperature stainless steel components for engines such as internal combustion engine poppet valves and valve components, illustratively casings, heads. stems claddings, linings, or surfacings which are importantly austenitic and contain chromium, nickel and molybdenum and have a critically lowsilicon content. In composition, my high temperature products include about 0.08% to 1.0%

carbon, from 15% to 30% chromium, 4.5% to 20% nickel, molybdenum in amounts from about 1% to 4.5%, silicon not exceeding 0.15% (silicon preferably not exceeding 0.09%), and the remainder substantially all iron. The carbon and molybdenum contents increase the metal hot-hardness. By keeping the silicon content at a value not exceeding 0.15% and preferably not exceeding about 0.09%, or even better at amounts ranging from 0.09% down to substantially zero, I find sharp improvement in resistance of the steel products to corrosion and attack by products of combustion resulting from the burning of leaded fuel.

A comparison of one of my steels, which is substantially austenitic, is illustrated in the accompanying drawing where the weight loss in molten lead oxide is plotted against the silicon values. This comparision is given for a number of 23% chromium-5% nickel-2% molybdenum stainless steels (Steels A, B, C, D, E and F in the following table) '4 to an amount not exceeding about 0.04%. Manganese, where present at all, seldom exceeds 1%. this elementnormally appearing in some small quantity as an incident to production of the steel.

Influence of silicon on corrosion-resistance of Cr-Ni-Mo valve steel in molten lead oxide Incidental or purposeful additions of nitrogen usually are present in the alloy metal of my products, and this preferably in amounts ranging up to about 0.01 times the amount of the chromium employed in the alloy composition. There are occasions too where my stainless steel valves and other products include as for special purposes, one or more such elements as titanium, columbium, tungsten, vanadium, cobalt, copper, tantalum, aluminum, zirconium. or the like, ranging 'from quite small to-substantial amounts not inconsistent with the properties desired.

By virtue of the substantially austenitic quality of the steel my valve products and other components are not susceptible to phase transformation during heating and cooling cycles and, accordingly, are free of change of phase. The valves, even where in the form of internal combustion engine exhaust poppet valves, are hard, strong and tough at the high temperatures encountered and are highly resistant to scour and the borrosive effects of the combustion products of leaded fuels. They reliably resist scaling, warping and cracking at full engine temperatures and upon being cooled and re-heated.

Thus'it will be seen that in this invention there are provided low-silicon austenitic chromium-- nickel-molybdenum stainless steel articles and products, in which the various objects noted hereinbeiore together with many thoroughly practical advantages are successfully achieved. It will be seen that the products are well suited for resisting corrosion in the presence of combustion products of leaded fuels.

While certain oi! the articles which I provide Weight Steel 0 Mn P s Gr Ni M0 B1 f f Oxide 70 low low 23. 75 4. 75 2. 75v 25 68. 51

All of the steels appearing in the table were exposed to molten lead oxide for 1 hour at 1675 F. The resulting weight loss as given in the table and plotted in the drawing, is in grams per square decimeter per hour. This weight loss decreases with a decrease in the silicon content, beginning with about 0.15% silicon. Thus, Steel A clearly is one of the low-silicon steels from which I make high temperature engine components.

A preferred example of my low-silicon steel is principally austenitic, containing about 0.50%

carbon, about 21% chromium, 6.5% nickel, about 2% molybdenum, silicon not exceeding 0.15% and preferably not exceeding about 0.09%, and the remainder substantially all iron.

The stainless steel in my valves, valve parts and other components preferably has a 10w sulphur and a low phosphorus content, for such reasons as avoiding the presence of substantial quantities of molybdenum compounds of these elements and thus contributing to ease of working and forming the metal to desired shape. Usually, I limit the sulphur and phosphorus in the alloy steel each take the form of internal combustion eng ne valves, valve parts and other internal combustion engine components, it will be understood that certain advantages of the invention are had from other products of the low-silicon steel, among which are high temperature gas turbine nozzles, turbine parts adjacent to the nozzle, and any of a variety of supercharger components.

As many possible embodiments may be made of my invention, and as many changes may be made in the embodiment hereinbefore set forth, it will be understood that all matter described herein is to be interpreted as illustrative and not as a limitation.

I claim:

1. Stainless steel having substantial hardness at high temperatures and substantial resistance to corrosion in the presence of leaded fuel combustion products, and containing about 0.35% to 1.0% carbon, about 15% to 30% chromium,

75 sure a substantially fully austenitic structure, silaccess:

5 icon not exceeding about 0.15%, and the remainder substantially all iron.

2. Austenitic stainless steel having substantial hardness at high temperatures and substantial resistance to corrosion in the presence of leaded fuel combustion products, and containing about 0.08% to 1.0% carbon, approximately 15% to 30% chromium, about 4.5% to 20% nickel, about 1% to 4.5% molybdenum, nitrogen ranging from extremely small amounts up to about 0.01 times the chromium, silicon not exceeding about 0.09%, and the remainder substantially all iron.

3. Austenitic stainless steel having substantial hardness at high temperatures and substantial resistance tocorrosion in the presence of leaded fuel combustion products, and containing about 0.35% to 1.0% carbon, about 23% chromium, approximately 5.0% nickel, about 3% molybdenum, silicon not exceeding about 0.09%, not more than about 1% manganese, sulphur and phosphorus each not exceeding about 0.04%, and the remainder substantially all iron.

4. An austenitic stainless steel having substantial hardness at high temperatures and substantial resistance to corrosion in the presence of leaded fuel combustion products, and containing about 0.08% to 1.0% carbon, about 15% to 30% chromium, about 4.5% to 20% nickel. about 1% to 4.5% molybdenum, silicon not exceeding about 0.09%, manganese below about 1%, sulphur and phosphorus each not exceeding about 0.04%, and the remainder substantially all iron.

5. An austenitlc stainless steel internal combustion engine valve having substantial hardness at high temperatures and substantial resistance to corrosion in the presence oi. leaded me]: combustion products, and containing about 0.08% to 1.0% carbon, approximately 15% to 30% ohmmium, about 4.5% to 20% nickel, about 1% to 4.5% molybdenum, silicon not exceeding about 0.15%, and the remainder substantially all iron.

-6. An austenitic stainless steel internal combustion engine exhaust valve having substantial hardness at high temperatures and substantial resistance to corrosion in the presence of leaded fuel combustion products, and containing about 0.35% to 1.0% carbon, about 28% chromium, approximately 5.0% nickel, about 3% molybdenum, silicon not exceeding about 0.09%, sulphur and phosphorus each not exceeding about 0.04%, and the remainder substantially all iron.

7.An austenitic stainless steel internal combustion engine exhaust valve having substantial hardness at high temperatures and substantial resistance to corrosion in the presence oi leaded fuel combustion products, and containing about 0.35% to 1.0% carbon, about 21% chromium, approximately 6.5% nickel, about 2% molybdenum, silicon not exceeding about 0.09%, and the remainder substantially all iron.

PAUL A. JENNINGS. REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PA'I'EN'rs 

1. STAINLESS STEEL HAVING SUBSTANTIAL HARDNESS AT HIGH TEMPERATURES AND SUBSTANTIAL RESISTANCE TO CORROSION IN THE PRESENCE OF LEADED FUEL COMBUSTION PRODUCTS, AND CONTAINING ABOUT 0.35% TO 1.0% CARBON, ABOUT 15% TO 30% CHROMIUM, ABOUT 4.5% TO 20% NICKEL, ABOUT 1% TO 4.5% MOLYBDENUM, ALL IN SUCH PROPORTIONS AS TO ASSURE A SUBSTANTIALLY FULLY AUSTENITIC STRUCTURE, SILICON NOT EXCEEDING ABOUT 0.15%, AND THE REMAINDER SUBSTANTIALLY ALL IRON. 